PPS Barrels

1. IMHO, brass provides the least friction against gelatin and the best opportunity to get it shaped and finished properly.
2. There seems to be a general "GADGETUDE" that wants to try to match a barrel to the paint being used. (of course this is promoted by those that want to sell barrels) It is far more important to match the barrel to the guns valveing and the way the expanding gas is used/released. The only other factor that I feel needs to be addressed in barrel selection is that of length. The variable that effects the decision of what length to use is temperature averages. As temperature raises, the gas is under higher pressure and is able to expand and accelerate faster, making a short barrel useable, but anything under approximately eight inches becomes counter productive in all but extremely warm conditions. On the other hand, colder weather slows down the expansion process and requires a little longer tube to allow things to get up to speed without wasting much of what is released by the valve. A barrel that is too long will also yield unfavorable results due to the extra gas needed to keep the ball moving past the point where desired velocity is reached. Too much gas generates a muzzle blast that effects the ball after it has left the barrel. Who knows what direction a ball will take when the gas blows past it outside of the guidance of the barrel. In most cases, 12" should be considered as the maximum effective length for a paintball barrel. The pressure options from a regulated high-pressure system will also affect the choices for "optimum" barrel length in much the same manner.
3. the texture and shape of the bore are both important to consistency and effectiveness. (FYI: Colin Thompson and I generated some huge phone bills with discussions over valving and launch tube shapes, while trying to come up with ways to achieve the right balance, many years ago.)
4. The way that we set up barrels here depends on the gun and its use. However, the basic concept is based on a shape that is slightly elliptical. A little tighter at the breech and muzzle than in the center section of the tube. The specific dimensioning will vary with the type and setup of the gun. We have had good results with shaping to meet the basic need of guns by brand but will usually achieve better results when we have THE specific gun to work with.